Tamiflu 75 mg (Oseltamivir): Uses, Safety and Interactions

What Tamiflu is used for

Tamiflu 75 mg capsules contain oseltamivir, an antiviral active against influenza viruses. This summary uses the UK product information and patient leaflet. It can be prescribed for influenza treatment or, in defined circumstances, prevention after exposure. Treatment and prevention are different plans. Tamiflu is not an antibiotic, does not treat every cause of flu-like symptoms and does not replace influenza vaccination.

Why timing and formulation matter

The cited label describes starting treatment promptly, generally within two days of symptoms for the studied uncomplicated-influenza setting. Clinical decisions also depend on illness severity, exposure, local influenza activity and official recommendations. Capsules, lower strengths and oral suspension have different practical roles, especially for children or people with swallowing difficulties. A 75 mg capsule is not automatically an appropriate dose for every age, body weight or level of kidney function. This page gives no instructions for making a liquid preparation or selecting a personal course.

Adverse effects and urgent symptoms

Nausea, vomiting, headache and abdominal discomfort are commonly reported. Some symptoms during treatment can also be caused by influenza itself. Rare serious effects include allergic reactions, severe skin reactions and liver problems. New confusion, hallucinations, unusual behaviour or seizures require prompt medical assessment, particularly in children and adolescents. Such neuropsychiatric events have also occurred in influenza patients who were not taking oseltamivir, so the observation alone does not prove that the medicine caused them. Repeated vomiting or worsening illness should be discussed with a clinician.

Interactions, kidney function and pregnancy

Oseltamivir has fewer CYP-mediated interactions than many other antivirals, but it is not interaction-free. Probenecid increases exposure to the active metabolite; the UK label does not require an adjustment for this combination in people with normal kidney function. Additional care is needed with certain medicines sharing renal elimination, including methotrexate. Kidney impairment may require changes to the prescribed regimen. Pregnancy and breastfeeding should be discussed promptly because influenza itself can pose risks, while treatment decisions depend on the clinical situation. Bring a complete medicine list rather than assuming an over-the-counter product is irrelevant.

Sources

• Roche: Tamiflu 75 mg hard capsules — UK SmPC — Text revised 1 January 2021; current emc listing checked 30 October 2026
• Roche: Tamiflu 75 mg hard capsules — UK patient leaflet — Current patient leaflet listed on emc; checked 30 October 2026

Source check: 30 October 2026. This records a source check, not a clinical review by a doctor or pharmacist. Follow the leaflet for the exact product supplied to you.